Plug-fuse



A L. EUSTICE.

PLUG FUSE.

APPLICATION FILED Aue.23, 1918.

1,344,296; Patented June 22, 1920.

,- frad L. Fu/sh ca,

T 0 all whom it may concern.

UNITED STATES PATENT orrlcs.

ALFRED L. EUSTICE, OF CHICAGO, ILLINOIS.

PLUG-FUSE.

Specification of Letters Patent. Pate t d J 22 1920.

Application filed August 23, 1918. Serial No. 251,091.

Be it known that I, ALFRED Eusrron, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Plug- Fuses, of whichthe following is a specification.

This invention relates to plug fuses.

One of the objects is to simplify and im prove the general constructionof plug fuses.

' Another object is to construct a plug fuse in a novel manner wherebyit can; be observed readily whether or not the fusible element hasbecome ineffective. 4

Another. object is to provide a novel plug fuse adapted to meet thevarious requirements for successful commercial usage.

These and other ob]ects are accomplished by means of the plug fusedisclosed on the accompanying sheet of drawings, in which- Figure 1 is aside elevation of my plug fuse F i g. 2 is an end'elevation of one endof the plug fuse;

Fig. 3 is an end elevation of the opposite end of the plug fuse; and

Figs. 4 and 5 are longitudinal sectional views of the same plug fuse onan enlarged scale taken at right angles with respect to each other.

The various novel features of my invention will be apparent from thefollowing description and drawings and will be particularly pointed outin the appended claims.

Referring to the figures of the drawings,

it will be noted that I have provided a plug fuse including a hollowbase 10 of'insulatmg material provided with a gnarled head 11 wherebythe plug fuse may be readily screwed into a socket. The barrel portionof this base 10 is provided with an external threaded portion 12 andwith a longitudinally extending groove 13 which interrupts the threads.A disk 14 of insulating material closes one end of the hollow base 10and is provided with two apertures 15 through which one end portion of afusible element 16 is threaded for forming one terminal, it beingunderstood that this end of the fusible element is doubled back uponitself on the inside of the disk 14 for secur- I ing the former to thelatter. The intermediate portion of the fusible element 16 extendsthrough the hollow barrel portion of the plug 10 and near the head ofthis base is provided with a drop-out link 17 formed by two narrow neckportions 18. Beyond this drop-out link portion, the'fusible elementextends toward the disk 14.- and passes to the outside of the fuse baseand occupies the groove 13. A threaded shell 17' of conducting materialis threaded over the threaded barrel portion of the base 10 and has aflange 18 which holds the disk 14 intermediate said flange 18 and oneend of the base 10. To make a good electrical contact between the shellterminal 17 and its cooperating end of the fusible member, a drop ofsolder may be used. The inter mediate looped portion of the fusibleelement 16 is supported by an insulating member 19, preferably of mica,which normally 1s supported in oppositely arran ed grooves 20 formed onthe inside of the barrel portion of the base 10. This insulating member19 also rests in a groove 21 on the inside of the disk 14 for preventingthe passage of a destructive are between oppositely arranged portions ofthe fusible element.

In order that the condition of the fusible element may be readilyobserved, I have provided the head end of the plu with a window 22,which preferably is 0 mica, or any other suitable transparent material,said window being held between oppositely arranged flanges 23 formedintegrally with a metal windowframe 24, the outer end of which, afterbeing inserted into the opening 25 of the base, is spun over at 26 toform a flange to prevent displacement of the frame, cooperatingin thisrespect with one of the flanges 23. It will be appreciated that theflanges 23 may be formed while assembling the window frame in the baseor may be formed previously thereto. If the fusible element is renderedineffective for any reason, the same will be served through the windowthe fuse may be repaired.

' By means of this arrangement a plug fuse readily ob- 22, whereuponsimple in construction and adapted for commercial usage is provided,

It is my intention to cover all modificathrough the apertured disk toform one terminal and having another portion extending along saidgroove, a conducting-terminal shell fitting over said base for securingthe disk thereto and being electrically connected to the fusibleelement, and a supporting member for an intermediate portion of thefusible member retained by'the grooves on the inside of said base.

2. A plug fuse including, in combination, a hollow base, a fusiblemember mounted therein, a flanged window frame mounted wholly within oneend of the base, and a transparent member mounted in said frame betweenits flanges whereby the transparent member is securely held and wherebythe condition of the fusible element may be observed.

3. A plug fuse including, in combination, a hollow base, a fusiblemember mounted therein, a flanged window frame mounted in one end of thebase, and a transparent member mounted in said frame between its flangeswhereby the transparent member is of the fuse, a fusible element havingone portion extending through the apertured disk to form one terminaland having another portion extending along said groove, said fusibleelement including a drop-out portion, a conducting terminal shellfitting over said base for securing the disk thereto and beingelectrically connected to the fusible member, and a transparent memberclosing the other end of the base and being arranged adjacent a drop-outportion of the fusible element whereby the condition of the fusibleelement may be observed.

Signed at Chicago, Illinois, this 17th day of August, 1918.

ALFRED L. EUSTICE.

